It depends on what is happening

If a person was to come up to you and push you, I think we can all agree that being pushed by some stranger is not enough to kill them over. But if you are attacked from behind and this person is trying to harm/kill you, I feel that you have the right to defend yourself and kill the person (if necessary)

Pinching you? NO. Verbal abuse? Not unless this includes them holding a weapon or making a fist while shouting threats at your life.

If there is a credible threat to your life or the permanent functioning of your body (say someone is threatening to make you a parapelgic) then it should be legal.

You should try to incapacitate rather than kill them but in the heat of the moment defending yourself you may not have time to stop and think "where's the best place to strike so they will be unlikely to die but will still be incapacitated?" so that's more of something people should do but specifying it in law could lead to a lot of people who were just doing the best to defend themselves being criminalized.